1. Field
Exemplary embodiments of the present invention relate to a semiconductor design technology, and more particularly, to an image sensor including a digital microlens and a method for fabricating the same.
2. Description of the Related Art
An image sensor is a semiconductor device which changes an optical image into an electrical signal. Image sensors include a plurality of pixels, which are arranged in a two-dimensional matrix. Each of the pixels includes a photoelectric conversion region which generates a photo-charge in response to incident light, and outputs a pixel signal corresponding to the incident light using the generated photo-charge.
Since the condensing (or concentrating) lens in conventional image sensors is curved, it has limited optical refraction efficiency. It has difficulty in applications where there is a large chief ray angle (CRA). To eliminate the above concerns, a novel digital microlens (DML) has been developed. The digital microlens concentrates light using a high refractive index layer and a low refractive index layer, and may be formed in a concavo-convex shape using a double pattern. However, the concavo-convex shape applied to a digital microlens may cause defective pixels due to its fabrication process.